Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Lyudmila Dobysheva]

12.09.2017, 18:48 +04:00 from Abderrahmane Reggad :
>Therefore I was satisfied with the study of the 3 configurations (nm, fm and 
>afmi) to find the afmI phase to be the most stable.
Then I do not understand: your "afmi" in fact becomes nonmagnetic, and its 
energy should be equal to nm case.

Best wishes
Lyudmila
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Thank you Gerhard for your advise

I read and I understand

What do you think if using the empirical parameters known give you
calculated values for band gap and magnetic moment ten times or more than
the experimental one.

Before using my value for alpha parameter, I used the alpha value equal to
0.25 which gives me a band gap equal to 1.6 eV for NiS which have an
experimental value equal to 0.eV.

If you want to know why I have used my value have a look to mu article in
the following link

http://www.sciencedirect.com/science/article/pii/S0921452617303915

I found that the empirical values (especially 0.25) are not suitable for 3d
transition metal sulphides.

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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Fecher, Gerhard]

Did you read and understand
   Rationale for mixing exact exchange with density functional approximations
   John P. Perdew, Matthias Ernzerhof, and Kieron Burke
   The Journal of Chemical Physics 105 , 9982 (1996)
or similar articles and references there ?

Usually, the parameters of the functionals (including hybrids) are well 
justified and not arbitrary numbers (even for the empirical functionals as 
B3LYP)
In my opinion it is bad habit to change functionals in an arbitrary way.
Indeed, one may in the same way change the parameters of the PBE-GGA (or any 
other LDA or GGA functional) until a calculation fits some property of some 
haphazardly selected material,
but what do we learn from such a procedure other than nonsense ?


Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Dienstag, 12. September 2017 16:57
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Hi Martin

I still confused and not convinced with my results.

It's not the band gap of NiS to take as the only criterion for the choice of 
the amount of excact exchange, but also the experimental values of magnetic 
moment. This amount allows me to get magnetic moment values close to the 
experimental values for many 3d transition metal sulphides like NiS, CrS, FeS 
and CoS.

For the use of EECE method for NiS semiconductor ; this later is not a sp 
semiconductor but  a splitting d bands semiconductor.


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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi Lyudmila

I have forgotten to add the article link

http://www.sciencedirect.com/science/article/pii/S0921452617303915
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi Martin

I still confused and not convinced with my results.

It's not the band gap of NiS to take as the only criterion for the choice
of the amount of excact exchange, but also the experimental values of
magnetic moment. This amount allows me to get magnetic moment values close
to the experimental values for many 3d transition metal sulphides like NiS,
CrS, FeS and CoS.

For the use of EECE method for NiS semiconductor ; this later is not a sp
semiconductor but  a splitting d bands semiconductor.


Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi Lyudmila

in the following article I studied the 3 different possible orderings for
the NiAs structure for the NiS compound and I found that the I-type order
is the most stable which is consistent which all theoritical and
experimental results.


It's found also that all transition metal compounds cristallizing in the
NiAs structure ( that I found ), if they are antiferromagnetic will be in
the I-type order. Therefore I was satisfied with the study of the 3
configurations (nm, fm and afmi) to find the afmI phase to be the most
stable.

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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Lyudmila Dobysheva]

11.09.2017, 17:24 +04:00 from Abderrahmane Reggad : I have 
repeated the calculation using ec and cc criterion equal to 0.1 and 0.0001 
respectively and I have found the magnetic moment to be lesser with the value 
of 0.0002 MB.

Maybe I missed the point in your discussion but I'd like to make some remark.
Imagine the experimental magnetic structure of a substance has a chess order:
udududududud
dudududududu
udududududud
dudududududu

And we start a calculation of another magnetic order, layers for example:





Then, actual magnetic interactions between moments should decrease them 
mutually, and the result will be the zero moment, at least can be, it depends.
I see that structure used here is layers:
H   LATTICE,NONEQUIV.ATOMS:  3 164_P-3m1   
  6.020859  6.020859 11.637259 90.00 90.00120.00   
ATOM  -1: X=0. Y=0. Z=0.
ATOM  -2: X=0. Y=0. Z=0.5000

Maybe it is worth thinking in this direction? Or you have discussed this 
already?

Best wishes
Lyudmila Dobysheva

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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[pieper]

Hi, A. Reggad

There are no questions in your last posts so the case seems to be 
closed.


However, I am curious, and there seems to be something to learn in 
addition to the nice comments made by G. Fecher:


First, is the band gap (of NiS) really a good observable to fix the HF 
mixing (for VS)? The user guide (ch. 4.5.7, first par.) says:


The onsite-exact- exchange/hybrid methods apply HF only
inside the atomic spheres and only to one particular
orbital. Thus you can use it only for localized electrons
(see [Tran et al., 2006] for details). Onsite- exact-exchange
will NOT improve gaps in sp-semiconductors.

These sulfides are not sp-semiconductors, but how reliable will this be 
here? Are those d-electrons localized?


Second, do you, A. Reggad, consider your 0.0002 mu_B to be zero? What 
about the AF order the Japanese experimentalists reported in the 
publication you yourself forwarded us? Any comments on the magnetic 
moment Prof. Fecher told us about?


Did you follow his advice?

Did you even read it?


---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 11.09.2017 15:55, schrieb Abderrahmane Reggad:

Hi Laurence

The amount of 0.05 of exact exchange is the value that gives a gap
value equal to the experimental one for nickel sulphide and close
values for magnetic moments for some 3d transition metal sulphides
like CrS, FeS, CoS and NiS.

You can check my article about the nickel sulphide

http://www.sciencedirect.com/science/article/pii/S0921452617303915

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Laurence Marks]

The only point I was making was that you have to be able to justify
whatever fraction is used.

On Sep 11, 2017 2:55 PM, "Abderrahmane Reggad"  wrote:

> Hi Laurence
>
> The amount of 0.05 of exact exchange is the value that gives a gap value
> equal to the experimental one for nickel sulphide and close values for
> magnetic moments for some 3d transition metal sulphides like CrS, FeS, CoS
> and NiS.
>
> You can check my article about the nickel sulphide
>
> http://www.sciencedirect.com/science/article/pii/S0921452617303915
> 
>
>
> Best regards
>
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi Laurence

The amount of 0.05 of exact exchange is the value that gives a gap value
equal to the experimental one for nickel sulphide and close values for
magnetic moments for some 3d transition metal sulphides like CrS, FeS, CoS
and NiS.

You can check my article about the nickel sulphide

http://www.sciencedirect.com/science/article/pii/S0921452617303915


Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Laurence Marks]

Why are you using 0.05 for the amount of exact exchange? You must justify
that this is valid (you, not me).

On Sep 11, 2017 2:24 PM, "Abderrahmane Reggad"  wrote:

> Hi all
>
> I have repeated the calculation using ec and cc criterion equal to 0.1
> and 0.0001 respectively and I have found the magnetic moment to be lesser
> with the value of 0.0002 MB.
>
> Here are the input files
>
> VS.struct
> ***
>
> VS-hex
>
> H   LATTICE,NONEQUIV.ATOMS:  3 164_P-3m1
>
> MODE OF CALC=RELA unit=ang
>
>   6.020859  6.020859 11.637259 90.00 90.00120.00
>
> ATOM  -1: X=0. Y=0. Z=0.
>   MULT= 1  ISPLIT= 4
> V 1NPT=  781  R0=0.5000 RMT=2.4200   Z:
> 23.0
> LOCAL ROT MATRIX:1.000 0.000 0.000
>  0.000 1.000 0.000
>  0.000 0.000 1.000
> ATOM  -2: X=0. Y=0. Z=0.5000
>   MULT= 1  ISPLIT= 4
> V 2NPT=  781  R0=0.5000 RMT=2.4200   Z:
> 23.0
> LOCAL ROT MATRIX:1.000 0.000 0.000
>  0.000 1.000 0.000
>  0.000 0.000 1.000
> ATOM  -3: X=0. Y=0.6667 Z=0.2500
>   MULT= 2  ISPLIT= 4
>   -3: X=0.6667 Y=0. Z=0.7500
> S 1NPT=  781  R0=0.0001 RMT=2.0800   Z:
> 16.0
> LOCAL ROT MATRIX:1.000 0.000 0.000
>  0.000 1.000 0.000
>  0.000 0.000 1.000
>   12  NUMBER OF SYMMETRY OPERATIONS
>
>
> VS.ineece
> 
>
> -12.0  2   emin natom
> 1 1 2 iatom nlorb lorb
> 2 1 2 iatom nlorb lorb
> EECE  HYBR / EECE mode
> 0.05  amount of exact exchange
>
> VS.indm
> **
>
> -12.  Emin cutoff energy
>  2   number of atoms for which density matrix is
> calculated
>  1  1  2  index of 1st atom, number of L's, L1
>  2  1  2  dtto for 2nd atom, repeat NATOM times
>  0 0   r-index, (l,s)index
>
> VS.inst
> *
>
> V
> Ar 2
> 3, 2,2.0  N
> 3, 2,1.0  N
> 4,-1,1.0  N
> 4,-1,1.0  N
> V
> Ar 2
> 3, 2,1.0  N
> 3, 2,2.0  N
> 4,-1,1.0  N
> 4,-1,1.0  N
> S
> Ne 3
> 3,-1,1.0  N
> 3,-1,1.0  N
> 3, 1,1.0  N
> 3, 1,1.0  N
> 3,-2,1.0  N
> 3,-2,1.0  N
> 
>  END of input (instgen_lapw)
>
> NB: Even in ferromagnetic (spin-polarized) calculation i found a similar
> value for magnertic moment.
>
>
> Best regards
>
>
>
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi all

I have repeated the calculation using ec and cc criterion equal to 0.1
and 0.0001 respectively and I have found the magnetic moment to be lesser
with the value of 0.0002 MB.

Here are the input files

VS.struct
***

VS-hex

H   LATTICE,NONEQUIV.ATOMS:  3
164_P-3m1
MODE OF CALC=RELA
unit=ang
  6.020859  6.020859 11.637259 90.00
90.00120.00
ATOM  -1: X=0. Y=0. Z=0.
  MULT= 1  ISPLIT= 4
V 1NPT=  781  R0=0.5000 RMT=2.4200   Z:
23.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -2: X=0. Y=0. Z=0.5000
  MULT= 1  ISPLIT= 4
V 2NPT=  781  R0=0.5000 RMT=2.4200   Z:
23.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -3: X=0. Y=0.6667 Z=0.2500
  MULT= 2  ISPLIT= 4
  -3: X=0.6667 Y=0. Z=0.7500
S 1NPT=  781  R0=0.0001 RMT=2.0800   Z:
16.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
  12  NUMBER OF SYMMETRY OPERATIONS


VS.ineece


-12.0  2   emin natom
1 1 2 iatom nlorb lorb
2 1 2 iatom nlorb lorb
EECE  HYBR / EECE mode
0.05  amount of exact exchange

VS.indm
**

-12.  Emin cutoff energy
 2   number of atoms for which density matrix is
calculated
 1  1  2  index of 1st atom, number of L's, L1
 2  1  2  dtto for 2nd atom, repeat NATOM times
 0 0   r-index, (l,s)index

VS.inst
*

V
Ar 2
3, 2,2.0  N
3, 2,1.0  N
4,-1,1.0  N
4,-1,1.0  N
V
Ar 2
3, 2,1.0  N
3, 2,2.0  N
4,-1,1.0  N
4,-1,1.0  N
S
Ne 3
3,-1,1.0  N
3,-1,1.0  N
3, 1,1.0  N
3, 1,1.0  N
3,-2,1.0  N
3,-2,1.0  N

 END of input (instgen_lapw)

NB: Even in ferromagnetic (spin-polarized) calculation i found a similar
value for magnertic moment.


Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi

Before doing the calculation again with the new energy and charge criterion
I let you this old article  http://journals.jps.jp/doi/abs/10.1143/JPSJ.14.196

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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Laurence Marks]

I would say that -cc 0.001 -ec 0.001 are certainly too large.

Also, a more subtle point. When you say you use "-eece" what hybrid
fraction? Is that the right fraction? How do you know if it is the right
value to use?

On Sep 8, 2017 9:13 AM, "Fecher, Gerhard"  wrote:

> Now I am a little confused
> do you think that it was the convergence criteria that I found a magnetic
> moment of 2.5 mu_B instead of 0.05 mu_B at the V ?
> or did I make another mistake ;-)
>
> Indeed, you are right, the 0.05 mu_B might be a result of to bad
> convergence
> however, to check if such a moment is something reliable you will need
> brute force with respect to the number of k-points,
> that is, if you think you have enough k-points, then just double the
> number or use ten times more.
>
> Ciao
> Gerhard
>
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
>
> 
> Dr. Gerhard H. Fecher
> Institut of Inorganic and Analytical Chemistry
> Johannes Gutenberg - University
> 55099 Mainz
> and
> Max Planck Institute for Chemical Physics of Solids
> 01187 Dresden
> 
> Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Gavin
> Abo [gs...@crimson.ua.edu]
> Gesendet: Freitag, 8. September 2017 03:14
> An: wien@zeus.theochem.tuwien.ac.at
> Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium
> sulphide
>
> Perhaps the -ec 0.001 and -cc 0.001 are too large of values.
>
> As I recall, to be well-converged, it is usually best to use about the
> default values seen in the post [1] or WIEN2k 17.1 usersguide [2] as:
>
> -cc 0.0001
> -ec 0.0001
>
> It sounded like about the default value for -ec was good unless something
> like -ec 0.1 was desired to reduce numerical noise, but anything
> smaller seemed useless [3,4].
>
> For -cc, 0.1 also may be the lowest limit [5] and quite ambitious to
> try to use [6].
>
> In section "4.5.4 Antiferromagnetic (AFM) calculations" on page 46 in the
> usersguide [2], there is the statement:
>
> "If nothing changes (E-tot and other properties), then you are ok,
> otherwise make sure the scf calculation is well converged (-cc 0.0001 or
> better)."
>
> If I read from the statement correctly, a well converged scf calculation
> typically uses -cc with a value of 0.0001 or smaller.  Though, there is a
> realistic limit as mentioned above on how small it could be set.
>
> In [7], it sounded important that the -cc value was low for the :MMIn
> values.
>
> So, maybe the calculation can still converge further such that possibly
> the "MMI for V1" and "MMI for V2" will both become zero when they reach
> better convergence.
>
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Fecher, Gerhard]

First, as Gavin told, your convergence criteria are too bad to decide about 
your magnetic moments
just try to improve them in steps say up to ec 10^-6 cc 10^-3 and see what 
happens with the moments
(that was why I asked fror it)
however be sure you have enough k-points

I assume you used the same structure (with split V position) and you were 
setting the initial moments of V in case.inst to 
nm   0 MU_B both V
fm3 mu_B both V
afm +3 mu_B -3 mu_B

now with GGA you find that all magnetic moments vanish (I assume 0.05 mu_B is 
just numerics)
that is you found a simple metal without magnetic moment that is most probably 
a paramagnet
(try to do a calculation for the fm start values using a very high magnetic 
field to check that)

If you plot the density of states or band structures, you will find that they 
are rather the same in all three cases.

What you missed  may be is a Mott insulator as for example NiO. In that case 
LDA+U is a good choice and you should find
fm = 2.5 mu_B   afm  =  +- 2.5 mu_B 
or at least something between 2 and 3 muB at the V atoms depending on your U 
value.
you should NOT start from the GGA or any LDA solution as they are non magnetic 
and the minimum of the magnetic solution
might be to far from the nonmagnetic one to be found, just start from scratch.
(that's why I asked for it)
You will also find that at least the afm solution has a gap.

in the same way you should find the magnetic solutions when using EECE or HYBR
with magnetic moments of at least about 2 mu_B.

So far, the magnetic moments might be from the spheres, a better way would be 
to use a Baader AIM analysis
to find the moments in the atomic basins here you can use the aim programs 
coming with Wien2k or the program CRITIC 2 from the software goodies.

Actually the existence of the "magnetic" solutions do NOT mean that this are 
the ground states and that those exist !

a) you should do an optimization of the lattice to find the structure for each 
magnetic state (for nm you may force a non-magnetic solution)
and then check which one has the lowest energy.

b) even this does not mean that the so determined state exists. Here you have 
to check whether the crystal is stable at all.
This can be done by calculating the elastic constants and veryfing the 
Born-Huang criteria and by calculating the phonons
to check that no soft modes appear that make the crystal unstable. 
Further you need to check that no soft magnon modes appear, otherwise the 
magnetic state is not stable.

About Hund's rules, please read and understand F Hund; Z. Phys. 33 (1925) 345
to find that those empirical rules are for free ATOMS.
There is a big difference between atoms and solids.
In atoms you have definit states that are occupied by integer numbers of 
electrons
In solids you have energy bands that my be occupied only partially
Immidiately you see that the results are not necessarily the same.
Magnetism in solids is a COLLECTIVE phenomenon (that is not possible in atoms) 
and the results may coincide or not depending whether or not you have purely 
localized, purely itinerant or mixed cases.
If one assumes that there are only covalent or ionic bonds then one just misses 
metals (and also rare gas solids).

There are many models to describe atoms, molecules and solids, however, one 
also needs to check which of those approximations is valid and applicable.


Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Donnerstag, 7. September 2017 17:11
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Hi All

I have used the PBE+EECC calculation for 3 configurations: nm, fm and afm I and 
I found that the afm I is the most stable.

The energy criterion and charge are 0.001 Ry and 0.001 e respectively.

I don't worry about if the material is really antiferromagnetic or paramagnetic 
because of:

1- I found only one experimental study that they found the compound to be pauli 
magnetic and one theoritical study which they found the compound to be non 
magnetic and these two studies are not sufficient to judge the compound to be 
in a such state. The theoritical study used the GGA method which is not good 
for correlated systems.

2- In the anfiferromagnetic state afm I in the NiAs structure for vanadium 
sulphide I found the following results:

MMI for V1: 0.05 MB
MMI for V2 :- 0.05 MB
MMI for S:0 MB

My questions are now:

what's the definition of non magnetic compound ?

Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Fecher, Gerhard]

Now I am a little confused
do you think that it was the convergence criteria that I found a magnetic 
moment of 2.5 mu_B instead of 0.05 mu_B at the V ?
or did I make another mistake ;-)

Indeed, you are right, the 0.05 mu_B might be a result of to bad convergence
however, to check if such a moment is something reliable you will need brute 
force with respect to the number of k-points,
that is, if you think you have enough k-points, then just double the number or 
use ten times more.

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Gavin Abo 
[gs...@crimson.ua.edu]
Gesendet: Freitag, 8. September 2017 03:14
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Perhaps the -ec 0.001 and -cc 0.001 are too large of values.

As I recall, to be well-converged, it is usually best to use about the default 
values seen in the post [1] or WIEN2k 17.1 usersguide [2] as:

-cc 0.0001
-ec 0.0001

It sounded like about the default value for -ec was good unless something like 
-ec 0.1 was desired to reduce numerical noise, but anything smaller seemed 
useless [3,4].

For -cc, 0.1 also may be the lowest limit [5] and quite ambitious to try to 
use [6].

In section "4.5.4 Antiferromagnetic (AFM) calculations" on page 46 in the 
usersguide [2], there is the statement:

"If nothing changes (E-tot and other properties), then you are ok, otherwise 
make sure the scf calculation is well converged (-cc 0.0001 or better)."

If I read from the statement correctly, a well converged scf calculation 
typically uses -cc with a value of 0.0001 or smaller.  Though, there is a 
realistic limit as mentioned above on how small it could be set.

In [7], it sounded important that the -cc value was low for the :MMIn values.

So, maybe the calculation can still converge further such that possibly the 
"MMI for V1" and "MMI for V2" will both become zero when they reach better 
convergence.

[1] https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg12620.html
[2] http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf
[3] https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg10650.html
[4] https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16077.html
[5] http://zeus.theochem.tuwien.ac.at/pipermail/wien/2008-November/011797.html
[6] https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg11558.html
[7] https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09231.html

On 9/7/2017 9:11 AM, Abderrahmane Reggad wrote:
Hi All

I have used the PBE+EECC calculation for 3 configurations: nm, fm and afm I and 
I found that the afm I is the most stable.

The energy criterion and charge are 0.001 Ry and 0.001 e respectively.

I don't worry about if the material is really antiferromagnetic or paramagnetic 
because of:

1- I found only one experimental study that they found the compound to be pauli 
magnetic and one theoritical study which they found the compound to be non 
magnetic and these two studies are not sufficient to judge the compound to be 
in a such state. The theoritical study used the GGA method which is not good 
for correlated systems.

2- In the anfiferromagnetic state afm I in the NiAs structure for vanadium 
sulphide I found the following results:

MMI for V1: 0.05 MB
MMI for V2 :- 0.05 MB
MMI for S:0 MB

My questions are now:

what's the definition of non magnetic compound ?

I think we can talk about non magnetic calculation and not about non magnetic 
compounds.

As Blaha said we can't silulate the paramagnetic state or at at least it's 
difficult to do it because we can't orientate the spins randomly ang maintain 
the total magnetic moment equals to zero.

Because of the Hind's prediction and because the impaired number of the V2+ ion 
to equal 3 I believe the atomic magnetic moment to be different from zero.

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Gavin Abo]

Perhaps the -ec 0.001 and -cc 0.001 are too large of values.

As I recall, to be well-converged, it is usually best to use about the 
default values seen in the post [1] or WIEN2k 17.1 usersguide [2] as:


-cc 0.0001
-ec 0.0001

It sounded like about the default value for -ec was good unless 
something like -ec 0.1 was desired to reduce numerical noise, but 
anything smaller seemed useless [3,4].


For -cc, 0.1 also may be the lowest limit [5] and quite ambitious to 
try to use [6].


In section "4.5.4 Antiferromagnetic (AFM) calculations" on page 46 in 
the usersguide [2], there is the statement:


"If nothing changes (E-tot and other properties), then you are ok, 
otherwise make sure the scf calculation is well converged (-cc 0.0001 or 
better)."


If I read from the statement correctly, a well converged scf calculation 
typically uses -cc with a value of 0.0001 or smaller. Though, there is a 
realistic limit as mentioned above on how small it could be set.


In [7], it sounded important that the -cc value was low for the :MMIn 
values.


So, maybe the calculation can still converge further such that possibly 
the "MMI for V1" and "MMI for V2" will both become zero when they reach 
better convergence.


[1] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg12620.html

[2] http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf
[3] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg10650.html
[4] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16077.html
[5] 
http://zeus.theochem.tuwien.ac.at/pipermail/wien/2008-November/011797.html
[6] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg11558.html
[7] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09231.html


On 9/7/2017 9:11 AM, Abderrahmane Reggad wrote:

Hi All

I have used the PBE+EECC calculation for 3 configurations: nm, fm and 
afm I and I found that the afm I is the most stable.


The energy criterion and charge are 0.001 Ry and 0.001 e respectively.

I don't worry about if the material is really antiferromagnetic or 
paramagnetic because of:


1- I found only one experimental study that they found the compound to 
be pauli magnetic and one theoritical study which they found the 
compound to be non magnetic and these two studies are not sufficient 
to judge the compound to be in a such state. The theoritical study 
used the GGA method which is not good for correlated systems.


2- In the anfiferromagnetic state afm I in the NiAs structure for 
vanadium sulphide I found the following results:


MMI for V1: 0.05 MB
MMI for V2 :- 0.05 MB
MMI for S:    0 MB

My questions are now:

what's the definition of non magnetic compound ?

I think we can talk about non magnetic calculation and not about non 
magnetic compounds.


As Blaha said we can't silulate the paramagnetic state or at at least 
it's difficult to do it because we can't orientate the spins randomly 
ang maintain the total magnetic moment equals to zero.


Because of the Hind's prediction and because the impaired number of 
the V2+ ion to equal 3 I believe the atomic magnetic moment to be 
different from zero.


Best regards
___
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[E.A.Moore]

Your calculations are probably fine.

Apologies for my previous posting but my point was partly that I think you said 
the  experimentalists claimed it was Pauli paramagnetic.

Pauli paramagnetism is not the type of paramagnetism that arises from unpaired 
electrons on metal ions in, for example, transition metal complexes. It is a 
property of metals. It arises if there is an unfilled conduction band. In an 
external magnetic field, one type of spin (up or down) acquires a different 
energy to the other type resulting in an excess of one type over the other and 
hence paramagnetism.

Both your result and the nonmagnetic finding are consistent with the existence 
of Pauli paramagnetism.

You results suggest that the 3 unpaired electrons on V are not localised on V 
but are in a delocalised band. Do you predict VS has a partially full 
conduction band?

Elaine A. Moore

From: Wien [mailto:wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
Abderrahmane Reggad
Sent: 07 September 2017 16:11
To: wien@zeus.theochem.tuwien.ac.at
Subject: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Hi All

I have used the PBE+EECC calculation for 3 configurations: nm, fm and afm I and 
I found that the afm I is the most stable.

The energy criterion and charge are 0.001 Ry and 0.001 e respectively.

I don't worry about if the material is really antiferromagnetic or paramagnetic 
because of:

1- I found only one experimental study that they found the compound to be pauli 
magnetic and one theoritical study which they found the compound to be non 
magnetic and these two studies are not sufficient to judge the compound to be 
in a such state. The theoritical study used the GGA method which is not good 
for correlated systems.

2- In the anfiferromagnetic state afm I in the NiAs structure for vanadium 
sulphide I found the following results:

MMI for V1: 0.05 MB
MMI for V2 :- 0.05 MB
MMI for S:0 MB

My questions are now:

what's the definition of non magnetic compound ?

I think we can talk about non magnetic calculation and not about non magnetic 
compounds.

As Blaha said we can't silulate the paramagnetic state or at at least it's 
difficult to do it because we can't orientate the spins randomly ang maintain 
the total magnetic moment equals to zero.

Because of the Hind's prediction and because the impaired number of the V2+ ion 
to equal 3 I believe the atomic magnetic moment to be different from zero.

Best regards
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi All

I have used the PBE+EECC calculation for 3 configurations: nm, fm and afm I
and I found that the afm I is the most stable.

The energy criterion and charge are 0.001 Ry and 0.001 e respectively.

I don't worry about if the material is really antiferromagnetic or
paramagnetic because of:

1- I found only one experimental study that they found the compound to be
pauli magnetic and one theoritical study which they found the compound to
be non magnetic and these two studies are not sufficient to judge the
compound to be in a such state. The theoritical study used the GGA method
which is not good for correlated systems.

2- In the anfiferromagnetic state afm I in the NiAs structure for vanadium
sulphide I found the following results:

MMI for V1: 0.05 MB
MMI for V2 :- 0.05 MB
MMI for S:0 MB

My questions are now:

what's the definition of non magnetic compound ?

I think we can talk about non magnetic calculation and not about non
magnetic compounds.

As Blaha said we can't silulate the paramagnetic state or at at least it's
difficult to do it because we can't orientate the spins randomly ang
maintain the total magnetic moment equals to zero.

Because of the Hind's prediction and because the impaired number of the V2+
ion to equal 3 I believe the atomic magnetic moment to be different from
zero.

Best regards
___
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi Gerhard

1- The charge criterion was 0.001 e
2- I didn't started from a converged PBE calculation
3- The amount of exact exchange use leads for results consistent with
experiment for the other 4 compounds.
5- Geometrical optimization leads to AFM 1 to be the most stable
6- i found only experimental study to predict the paramagnetic state


I hope I answer well your question

Best regards and many thanks
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Gavin Abo]

The problem is that I want to know if it's possible to get a such 
value of 0.05 MB for atomic magnetic moment for the AFM state of 
vanadium sulphide in NiAs structure.


Correct me if I'm wrong, but I believe you are saying that you opened 
the case.scf file in a text editor or did a "grep -e :MMTOT -e :MMI -e 
:MMINT *.scf", then got the values from the last ITERATION.  The :MMIn 
being the total spin magnetic moment [1,2].


The :MMIn for the V atoms having 0.05 μB or -0.05 μB. The :MMTOT, :MMIn 
for the S atoms, and :MMINT are 0 μB.


Thus, you have some like:

0 (for :MMTOT) = [0.05 μB * multiplicity + -0.05 μB * multiplicity] (for 
:MMIn of V atoms; this showing the canceling moments of an AFM 
configuration [3]) + 0 (for :MMIn of S atoms) + 0 (for :MMINT)



  what was your charge convergence criterion ?


In addition to needing know what was used for -cc, maybe they would also 
need to know how :MMIn behaved in the last several iterations like in 
the posts [4,5].


[1] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg12562.html
[2] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg10483.html
[3] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg13159.html
[4] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09231.html
[5] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09190.html

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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[pieper]

I agree, there is some confusion. There probably always is.

The confusion here is mainly about definition para-, dia-, ferro-, 
antiferro-, heli-, or non-  magnetic. This comes up every now and then.


As I said before, I like the following distinction.

a) Define Non-Magnetic ONLY in context of calculations, and there as a 
model where in the converged ground state all local moments are smaller 
than the numerical noise.


The rest were defined much earlier from an experimental point of view. 
They all are meant to distinguish response to external magnetic field - 
a field that DOES NOT EXIST in your off the shelf DFT!


b) Various kinds of dia- and para-magentism specify wether the 
magnetization induced by an applied field is opposite (diamagnetic) or 
parallel (paramagnetic) to the field.


c) Magnetically ordered states (FM, AFM of various types, ferri-, heli-, 
spin density wave-, ...) are PM in this sense. They are distinguished by 
the spacial arrangement of non-zero static magnetic moments (all 
parallel, exactly compensated antiparallel, not compensated 
antiparallel, not collinear, varying in size continuously, ...).




So in response to your points:

1.: Yes, but a PM response just might be due to some unnoticed AF 
ordered state. Because of Ockham's razor one would have to convince me 
of that, but who know's?


2.: Yes, you can get a non-magnetic ground state from a spin-resolved 
calculation. 'Local moments' always refers to the moments within RMT's 
(or whatever the DFT code supports to assign local moments). The 
electron spins are of course always there, but spin up and down can 
compensate - and often will compensate due to spin degenerate ground 
states.


3.: No, I would be very surprised (and suspicious) if the calculations 
yield some exactly compensating moment on S. For exact compensation, 
that is an AF arrangement, you have to have the same element pointing 
moments in opposite directions. Even the crystalografic lattice sites 
occupied by the antiparallel moments should be the same. I know of no 
counter example but would be interested if there is one. In VS Vanadium 
just might split one of its sublattices into such an AF arrangement.


4.: There is a DOS plotted in the work A. Reggad linked in his earlier 
question.


5.: That DOS certainely looks metalic and the authors claim agreement 
with experiment.


Best regards,

Martin Pieper



---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 07.09.2017 11:02, schrieb E.A.Moore:

I have been following this thread and I think there is some confusion.

1. On the thread it said that the experiment showed it was Pauli
paramagnetic. This is the type of magnetism displayed by some metals
e.g. sodium which is only apparent if you apply a magnetic field.

2. If you include spin in your calculation (GGA or GGA + U) you can
only get ferromagnetic, antiferromagnetic or ferromagnetic states. (An
earlier thread deals with how to get paramagnetic states). I think you
can only get a nonmagnetic state if you do not include spin? A
material with Pauli paramagnetism will be antiferromagnetic in
straight forward spin-including calculations.

3. I assume the 0.05 muB refers to the magnetic moment on V. If
vanadium sulphide is antiferromagnetic and the magnetic moment on
Vanadium is 0.05 muB, then there must be a balancing magnetic moment
on the sulphur.

4. I suspect this compound might be alloy-like. Is there considerable
mixing of V and S in the valence bands?

5. Assuming your formula is VS, it might be worth noting that VO shows
some metallic physical properties.

Elaine A. Moore
Reader in theoretical chemistry
The Open University



-Original Message-
From: Wien [mailto:wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf
Of Fecher, Gerhard
Sent: 07 September 2017 08:12
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] About the magnetic moment of vanadium in vanadium 
sulphide


0.05 muB does not mean that it is antiferromagnetic ! what was your
charge convergence criterion ?

You did never answer my question whether you started the EECE
calculation from a converged GGA calculation.

Why do you like to have an afm state when the experiment tells it is 
not ?


Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you, is that you have
never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - 
University

55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von
Abderrahmane Reggad [jazai...@gmail.com]
Gesendet: Donnerstag, 7. September 2017 00:26
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium 

Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[E.A.Moore]

 I am used to setting up calculations with spins set to be parallel or 
antiparallel to each other and I would probably class those set up with 
antiparallel spins as AFM. You can also set up calculations that don't include 
spin and so will not have any magnetic moments. I tend to regard these as 
nonmagnetic calculations. However I take the point that something set up as AFM 
could turn out to have a 0 magnetic moment. 

Sorry you are right it should be the V magnetic moments that balance out. 

A Pauli paramagnet should have 0 magnetic moment from these calculations (it 
could be antiferromagnetic or nonmagnetic) as the magnetic moment is only 
produced when a magnetic field is applied.

-Original Message-
From: Wien [mailto:wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
Fecher, Gerhard
Sent: 07 September 2017 10:39
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Sorry but there is obviously a lot of nonsense in the comments where you should 
first think about:

Please explain why a spin polarized calculation will always result in a 
ferromagnetic (or antiferromagnetic) state ? How do you define a ferromagnet 
(or antiferromagnet) ?  
What happens when the magnetic part of the Hamilton becomes Zero in a spin 
polarized calculation ? What is a ferromagnet or antiferromagnet without 
magnetic moments at the atoms ?
Why should a paramagnet become an antiferromagnet in the calculation ?

Why is VS an antiferromagnet when V has a magnetic moment of 0.05 muB and S one 
of -0.05 muB ? Don't you think it is possible that the magnetisation of two V 
atoms may have to cancel ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you, is that you have never 
actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von E.A.Moore 
[e.a.mo...@open.ac.uk]
Gesendet: Donnerstag, 7. September 2017 11:02
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

I have been following this thread and I think there is some confusion.

1. On the thread it said that the experiment showed it was Pauli paramagnetic. 
This is the type of magnetism displayed by some metals e.g. sodium which is 
only apparent if you apply a magnetic field.

2. If you include spin in your calculation (GGA or GGA + U) you can only get 
ferromagnetic, antiferromagnetic or ferromagnetic states. (An earlier thread 
deals with how to get paramagnetic states). I think you can only get a 
nonmagnetic state if you do not include spin? A material with Pauli 
paramagnetism will be antiferromagnetic in straight forward spin-including 
calculations.

3. I assume the 0.05 muB refers to the magnetic moment on V. If vanadium 
sulphide is antiferromagnetic and the magnetic moment on Vanadium is 0.05 muB, 
then there must be a balancing magnetic moment on the sulphur.

4. I suspect this compound might be alloy-like. Is there considerable mixing of 
V and S in the valence bands?

5. Assuming your formula is VS, it might be worth noting that VO shows some 
metallic physical properties.

Elaine A. Moore
Reader in theoretical chemistry
The Open University



-Original Message-
From: Wien [mailto:wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
Fecher, Gerhard
Sent: 07 September 2017 08:12
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

0.05 muB does not mean that it is antiferromagnetic ! what was your charge 
convergence criterion ?

You did never answer my question whether you started the EECE calculation from 
a converged GGA calculation.

Why do you like to have an afm state when the experiment tells it is not ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you, is that you have never 
actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Donnerstag, 7. September 2017 00:26
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Hi Martin

The problem is that I want to know if it's possible to get a such value of 0.05 
MB for atomic magnetic moment for the AFM state of vanadium sulphide in 

Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[pieper]

Your problem is 'if it's possible to get' AF VS with 0.05 mu_B/Vanadium 
in DFT?
IF (capitals are on purpose here) you did everything right to properly 
converge your calculations to the necessary numerical precision, then 
you give the answer yourself: Yes, it is possible if one uses GGA+U or 
+EECE.


Wether or not this is an improved model of VS remains open. You still 
did very little to convince Prof. Fecher or me that you actually did 
things right to achieve that precision.  And you did even less to 
convince me (us) that experiments might have missed the small moment.


Even if you are convinced of both, that you did everything right and the 
experimentalists did something wrong, you still should discuss very 
carefully the physics behind your decision to improve the model of a 
metal by introducing a local orbital potential.


You probably don't need to convince us, but keep it in mind for fights 
with the referees of a publication on this.


Good luck with your calculations

Martin Pieper

---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 07.09.2017 00:26, schrieb Abderrahmane Reggad:

Hi Martin

The problem is that I want to know if it's possible to get a such
value of 0.05 MB for atomic magnetic moment for the AFM state of
vanadium sulphide in NiAs structure.

Hafner and Hobbs have found all the calculations converged to the non
magnetic state because they have used the GGA method. To get the AFM
state they have to use either the EECE or GGA+U methods.

I hope you touch the problem

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Fecher, Gerhard]

Sorry but there is obviously a lot of nonsense in the comments where you should 
first think about:

Please explain why a spin polarized calculation will always result in a 
ferromagnetic (or antiferromagnetic) state ? How do you define a ferromagnet 
(or antiferromagnet) ?  
What happens when the magnetic part of the Hamilton becomes Zero in a spin 
polarized calculation ? What is a ferromagnet or antiferromagnet without 
magnetic moments at the atoms ?
Why should a paramagnet become an antiferromagnet in the calculation ?

Why is VS an antiferromagnet when V has a magnetic moment of 0.05 muB and S one 
of -0.05 muB ? Don't you think it is possible that the magnetisation of two V 
atoms may have to cancel ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von E.A.Moore 
[e.a.mo...@open.ac.uk]
Gesendet: Donnerstag, 7. September 2017 11:02
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

I have been following this thread and I think there is some confusion.

1. On the thread it said that the experiment showed it was Pauli paramagnetic. 
This is the type of magnetism displayed by some metals e.g. sodium which is 
only apparent if you apply a magnetic field.

2. If you include spin in your calculation (GGA or GGA + U) you can only get 
ferromagnetic, antiferromagnetic or ferromagnetic states. (An earlier thread 
deals with how to get paramagnetic states). I think you can only get a 
nonmagnetic state if you do not include spin? A material with Pauli 
paramagnetism will be antiferromagnetic in straight forward spin-including 
calculations.

3. I assume the 0.05 muB refers to the magnetic moment on V. If vanadium 
sulphide is antiferromagnetic and the magnetic moment on Vanadium is 0.05 muB, 
then there must be a balancing magnetic moment on the sulphur.

4. I suspect this compound might be alloy-like. Is there considerable mixing of 
V and S in the valence bands?

5. Assuming your formula is VS, it might be worth noting that VO shows some 
metallic physical properties.

Elaine A. Moore
Reader in theoretical chemistry
The Open University



-Original Message-
From: Wien [mailto:wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
Fecher, Gerhard
Sent: 07 September 2017 08:12
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

0.05 muB does not mean that it is antiferromagnetic ! what was your charge 
convergence criterion ?

You did never answer my question whether you started the EECE calculation from 
a converged GGA calculation.

Why do you like to have an afm state when the experiment tells it is not ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you, is that you have never 
actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Donnerstag, 7. September 2017 00:26
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Hi Martin

The problem is that I want to know if it's possible to get a such value of 0.05 
MB for atomic magnetic moment for the AFM state of vanadium sulphide in NiAs 
structure.

Hafner and Hobbs have found all the calculations converged to the non magnetic 
state because they have used the GGA method. To get the AFM state they have to 
use either the EECE or GGA+U methods.

I hope you touch the problem


Best regards
___
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Wien@zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.
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Wien@zeus.theochem.tuwien.ac.at

Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[E.A.Moore]

I have been following this thread and I think there is some confusion.

1. On the thread it said that the experiment showed it was Pauli paramagnetic. 
This is the type of magnetism displayed by some metals e.g. sodium which is 
only apparent if you apply a magnetic field.

2. If you include spin in your calculation (GGA or GGA + U) you can only get 
ferromagnetic, antiferromagnetic or ferromagnetic states. (An earlier thread 
deals with how to get paramagnetic states). I think you can only get a 
nonmagnetic state if you do not include spin? A material with Pauli 
paramagnetism will be antiferromagnetic in straight forward spin-including 
calculations.

3. I assume the 0.05 muB refers to the magnetic moment on V. If vanadium 
sulphide is antiferromagnetic and the magnetic moment on Vanadium is 0.05 muB, 
then there must be a balancing magnetic moment on the sulphur.

4. I suspect this compound might be alloy-like. Is there considerable mixing of 
V and S in the valence bands?

5. Assuming your formula is VS, it might be worth noting that VO shows some 
metallic physical properties.

Elaine A. Moore
Reader in theoretical chemistry
The Open University



-Original Message-
From: Wien [mailto:wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
Fecher, Gerhard
Sent: 07 September 2017 08:12
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

0.05 muB does not mean that it is antiferromagnetic ! what was your charge 
convergence criterion ?

You did never answer my question whether you started the EECE calculation from 
a converged GGA calculation.

Why do you like to have an afm state when the experiment tells it is not ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you, is that you have never 
actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Donnerstag, 7. September 2017 00:26
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Hi Martin

The problem is that I want to know if it's possible to get a such value of 0.05 
MB for atomic magnetic moment for the AFM state of vanadium sulphide in NiAs 
structure.

Hafner and Hobbs have found all the calculations converged to the non magnetic 
state because they have used the GGA method. To get the AFM state they have to 
use either the EECE or GGA+U methods.

I hope you touch the problem


Best regards
___
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Wien@zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.
___
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Fecher, Gerhard]

0.05 muB does not mean that it is antiferromagnetic ! what was your charge 
convergence criterion ?

You did never answer my question whether you started the EECE calculation from 
a converged GGA calculation.

Why do you like to have an afm state when the experiment tells it is not ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Donnerstag, 7. September 2017 00:26
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Hi Martin

The problem is that I want to know if it's possible to get a such value of 0.05 
MB for atomic magnetic moment for the AFM state of vanadium sulphide in NiAs 
structure.

Hafner and Hobbs have found all the calculations converged to the non magnetic 
state because they have used the GGA method. To get the AFM state they have to 
use either the EECE or GGA+U methods.

I hope you touch the problem


Best regards
___
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Wien@zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Hi Martin

The problem is that I want to know if it's possible to get a such value of
0.05 MB for atomic magnetic moment for the AFM state of vanadium sulphide
in NiAs structure.

Hafner and Hobbs have found all the calculations converged to the non
magnetic state because they have used the GGA method. To get the AFM state
they have to use either the EECE or GGA+U methods.

I hope you touch the problem


Best regards
___
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http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[pieper]

I took an admittedly brief look at your link, and I still don't 
understand where your problem really is.


I have made calculations for 5 3d transition metal sulphides with the 
method PBE+EECE and I have found that all the results are ok with the 
exception of the vanadium sulphide.


I have made 3 calculations (nm, fm and afmI ) to determine the magnetic 
state for all the compounds and I found them to have afm state.


What exactly is the discrepancy between your results and the state Hobbs 
and Hafner found? You did not answer Prof. Fechers and my question about 
the size of the moment you calculated. Nor my question of wether you 
find an insulator or a metal. Especially in case of the latter I might 
ask about your insistance on Hund's rule ...


The problem is about the atomic magnetic moment of vanadium and for the 
other results which are not reliable because there is one study where 
they used the non magnetic and paramagnetic states with the same 
meaning which is contrary to what said Pr Blaha and they mentionned 
that they have found to be non magnetic without details.


At a glance, those authors seem, in fact, to distinguish between 'non 
magnetic' and 'paramgentic': NM is used with respect to results of their 
calculations for cases where in the ground state all moments are zero 
(or below some numerical threshold). PM is used for states observed in 
experiments where it is defined by the response of the sample to a 
magnetic field (which they - and you - don't calculate). Not a bad idea, 
as far as I am concerned.


And they do give details on VS in section 3.1 - in fact, a lot more 
details than you give us here about your calculations.


Best regards

---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 06.09.2017 03:59, schrieb Abderrahmane Reggad:

I have made calculations for 5 3d transition metal sulphides with the
method PBE+EECE and I have found that all the results are ok with the
exception of the vanadium sulphide.

I have made 3 calculations (nm, fm and afmI ) to determine the
magnetic state for all the compounds and I found them to have afm
state.

The problem is about the atomic magnetic moment of vanadium and for
the other results which are not reliable because there is one study
where they used the non magnetic and paramagnetic states with the same
meaning which is contrary to what said Pr Blaha and they mentionned
that they have found to be non magnetic without details.

You will find the study in the following link

https://www.researchgate.net/profile/J_Hafner/publication/216328826_Magnetism_and_magneto-structural_effects_in_transition-metal_sulfides/links/00463525eaa9e1230f00.pdf

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

I have made calculations for 5 3d transition metal sulphides with the
method PBE+EECE and I have found that all the results are ok with the
exception of the vanadium sulphide.

I have made 3 calculations (nm, fm and afmI ) to determine the magnetic
state for all the compounds and I found them to have afm state.

The problem is about the atomic magnetic moment of vanadium and for the
other results which are not reliable because there is one study where they
used the non magnetic and paramagnetic states with the same meaning which
is contrary to what said Pr Blaha and they mentionned that they have found
to be non magnetic without details.

You will find the study in the following link

https://www.researchgate.net/profile/J_Hafner/publication/216328826_Magnetism_and_magneto-structural_effects_in_transition-metal_sulfides/links/00463525eaa9e1230f00.pdf

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[pieper]

High A. Reggad,

substitute V for Cr in Prof. Fecher's questions, otherwise I am with 
him.


In case you refer by 'almost zero' to the 0.05 mu_B I seem to recall 
from your original question, and now wonder about some fundamental 
discrepancy between the supposed experimental Pauli paramagnetism and 
your supposed antiferromagnetism: Take a VERY close look at both, 
experiment AND calculations.


It is not trivial to experimentally distinguish a PM from an AF with 
such a small moment, especially if you have no idea that there is a Tc, 
let alone where it is. The, say T-dependant SQUID, measurement could 
start already in the AF state if Tc is above RT and never realize the 
state is already AF. Or maybe Tc is below the lowest T the experimental 
set-up could reach?


It is equally not trivial to establish an AF ground state with that 
precision from DFT. Did you consider MMI of V as convergence criterium? 
Did you check convergence to that precision with respect to RKMAX, 
k-mesh, ... ? Did you keep the k-mesh (symmetries) between your 
calculations of the PM and the AF? Did you force the AF structure in 
your calculation? Did you try what happens if you don't impose it? Are 
you shure about your structural data? Did you do structural relaxation? 
Does structural relaxation influence your result of a magnetic ground 
state? What about the influence of the xc-potential? Did you do eece 
with LSDA or with PBE-GGA or with ...?


And what about other physical properties? Maybe most important, is the 
stuff metallic/insulating in experiment/calculations?


In case your question is about this horrible violation of Hund's rules, 
I repeat my former suggestion: Take a close look at the assumptions 
these rules rely on. And never forget that any law and rule of physics 
is valid only within some domain more or less clearly defined by such 
assumptions.




---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 05.09.2017 07:45, schrieb Fecher, Gerhard:

About what moment are you talking,
the total magnetic moment or the magnetic moment of the Cr atoms ?

Did you start your EECE calculation from a regular GGA calculation
that had no magnetic moments at the Cr ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von
Abderrahmane Reggad [jazai...@gmail.com]
Gesendet: Dienstag, 5. September 2017 00:29
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium 
sulphide


Thanks martin

Experimentally they found that the vanadium sulphide is a pauli
paramagnetic but I have found it to be antiferromagnetic like other
transition metal sulphides but the magnetic moment value equals almost
zero despite the fact that vanadium has 3 inpaired electrons.

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Fecher, Gerhard]

About what moment are you talking,
the total magnetic moment or the magnetic moment of the Cr atoms ?

Did you start your EECE calculation from a regular GGA calculation that had no 
magnetic moments at the Cr ? 

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Dienstag, 5. September 2017 00:29
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

Thanks martin

Experimentally they found that the vanadium sulphide is a pauli paramagnetic 
but I have found it to be antiferromagnetic like other transition metal 
sulphides but the magnetic moment value equals almost zero despite the fact 
that vanadium has 3 inpaired electrons.

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Thanks martin

Experimentally they found that the vanadium sulphide is a pauli
paramagnetic but I have found it to be antiferromagnetic like other
transition metal sulphides but the magnetic moment value equals almost
zero despite the fact that vanadium has 3 inpaired electrons.

Best regards
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Re: [Wien] About the magnetic moment of vanadium in vanadium sulphide

[pieper]

Be aware that Hund's rules do rest on certain assumptions about the 
relative strength of intra- and inter-atomic couplings. There are, after 
all, a lot of para- or diamagnetic materials around. Try to look that 
up. Is your Vanadium sulphide magnetically ordered from experiment?


In your case the 0.05 mu_B is probably an instance of the problems 
frequently encountered in strongly correlated systems: There are several 
states with very similar total energy, but with very different 
configurations of charges and spins. Search the mailing list for 
magnetic ordered states, or for orbital order.


The scf cycle of DFT will tend to stay near the configuration it started 
from. If you start from a standard non-magnetic configuration set by 
lstart it won't look at magnetically ordered states. Try to start the 
scf cycle from magnetic configurations - you can set them up in lstart - 
and compare the total energies. Be carefull to change only the magnetic 
starting configuration, NOT RMT's, RKMAX, K-mesh, crystal symmetry, 
whatever.


Note that the starting spin configurations you can set in lstart may 
well be not good enough. You may have to modify the density matrix of 
the problematic orbitals by hand and let the scf cycle dig itself in in 
that state by using the option -orbc. This also has been explained in 
posts in this mailing list before - perhaps most detailed by prof. Tran.


Good luck with your calculations

---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 02.09.2017 12:24, schrieb Abderrahmane Reggad:

Dear wien2k users

I have calculated the magnetic moment of  vanadium sulphide in NiAs
structure using the EECE méthod with alpha parameter equals to 0.05.

despite the fact that the number of inpariated electrons is equal to 3
I found that the magnetic moment of vanadium is equal to 0.05 MB which
is inconsistent with the prediction of Hund.

Best regards
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[Wien] About the magnetic moment of vanadium in vanadium sulphide

[Abderrahmane Reggad]

Dear wien2k users

I have calculated the magnetic moment of  vanadium sulphide in NiAs
structure using the EECE méthod with alpha parameter equals to 0.05.

despite the fact that the number of inpariated electrons is equal to 3 I
found that the magnetic moment of vanadium is equal to 0.05 MB which is
inconsistent with the prediction of Hund.


Best regards
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